1. Field of the Invention
This invention relates to a battery-connecting plate for use with a battery holder which receives a large number of cylindrical batteries and which is mounted as in an electric vehicle, a method of producing same, and a wire protector.
2. Description of the Related Art
A battery-connecting plate 100 as shown in FIGS. 18A, 18B is conventionally used as a means of connecting a plurality of batteries in series or in parallel.
The connecting plate 100 includes a molded resin plate 103, a busbar 102 for connecting two batteries 101, fixed in the resin plate 103 by molding, the two batteries having nut-type positive and negative electrodes 101a, 101b, and a hexagonal and a square windows 103a, 103b in which electrode-connecting busbar holes 102a are exposed. The connection of the two batteries 101 is effected by fastening the busbar 102 to the nut-type positive and negative electrodes 101a, 101b with the bolts 104, at which time at the hexagonal window 103a a round terminal 105, which constitutes part of a voltage detecting circuit, is concurrently connected. In other words, the wire 106 connected to the round terminal 105 has a fuse 108 interposed in series therein and extends therefrom to a not-shown ECU. The fuse 108, which is enclosed in a fuse casing 107, is connected at its opposite ends, via a female terminal 109, to the wire 106.
FIG. 19 shows another example of a conventional connecting plate.
The connecting plate 100xe2x80x2 includes a molded resin plate 103 and a plurality of L-shaped busbars 102xe2x80x2 fixed in the resin plate 103 by molding, the L-shaped busbars having connection legs 102bxe2x80x2 of different lengths which have one end projected at one side of the molded resin plate 103. A wire 106 is welded at one end to the thus projected end of each L-shaped busbar and extends, via a fuse 108xe2x80x2 enclosed in a fuse casing 107xe2x80x2, to a not-shown ECU.
The fuse casing 107xe2x80x2 includes a base plate 110 and a pair of opposed L-shaped pressure-welding terminals 111 provided on the base plate, the pair of terminals 111 each having a base plate 111a whereat the wire 106 is welded and a pressure-welding piece 111b with a slot 111c rising from the base plate 111a, and the fuse 108 having its leads 108axe2x80x2 pressure-welded via the slots 111c to the respective pressure-welding pieces 111b. 
The connecting plate 100 of FIG. 18 requires many connections in one circuit, for example, six connections in the voltage detecting circuit as shown at characters a, b . . . f, and also requires a large components count, possibly resulting in reliability in electric connection lowered. Further, the wired round terminals 105 require a manual operation one by one during their bolting, and hence as the number of wires 106 increases, it will become troublesome to bolt the round terminals 105 and to lay their wires 106.
On the other hand, the connecting plate 100xe2x80x2 of FIG. 19 requires L-shaped busbars 102xe2x80x2 of different sizes, and hence is disadvantageous in the production cost of the L-shaped busbars and their administration. Further, as is the case of the connecting plate 100, there are required a large components count and a large connections count in one circuit (five connections of axe2x80x2, bxe2x80x2 . . . exe2x80x2), and besides difficulty is encountered in protecting the welds between the wires 106 and their corresponding connection legs 102bxe2x80x2. 
Further, the connection wires 106 of the connecting plates 100, 100xe2x80x2, being directly connected to the related batteries 101, need to be properly protected. Due to the bulky member of the fuse casing 107, 107xe2x80x2 interposed, however, such a protection structure will inevitably become complicated.
FIG. 20 shows the case in which batteries are connected together not with a connecting plate, but directly with wires. In other words, each prism-shaped battery 101xe2x80x2 has positive and negative electrodes 101axe2x80x2, 101bxe2x80x2 juxtaposed at one end, a main power wire 112 is used to connect neighboring batteries to each other, and wires 106 each with a fuse casing 107 (voltage detecting circuits), as in the case of FIG. 18, are connected to predetermined electrodes 101bxe2x80x2. 
Also in this case, a large components count is required. Further, the wires are dangerously exposed at many portions. In addition, due to the intersecting main power wires 112 and voltage detecting circuit constituting wires 106, the wiring becomes complicated so as to cause an improper wiring.
Under these conditions, it is conceived to embed the connection wires 106 of the connecting plate 100, 100xe2x80x2 in the molded resin plate 103 by insert molding.
With a conventional method of insert molding, however, as shown in FIGS. 21A, 21B, the wires 113, although firmly fixed inside the molded resin plate 114, become free outside the plate. Consequently, concentration of stress tends to take place at the roots 113a of the wires 113 located at the edge of the molded resin plate 114, so that in extreme cases the wires 113 are cut at the roots 113a by the action of a minimal external force. To prevent this, it is conceived to bundle the wires 113 with a band 115 or to fix the wires to a wall of the molded resin plate 114 through a fixture. The concentration of stress at the roots 113a, however, cannot be fully precluded, because the above operation is effected only after completion of the insert molding.
Further, there remains another cause of the cutting of the wires 113 at the roots 113a, which is the biting by the upper and lower dies 116 at the outlet of the wires.
Further, with a conventional method of insert molding, because, as shown in FIG. 22, the molten resin injected from the nozzle 119 of a molding machine into the mold 116 has a temperature higher than the heat-resisting temperature of the insulating cover 113b of commonly used wires 113, it has been required to use heat-resistant wires covered as with polyimide, resulting in a cost increase.
This invention has been accomplished to overcome the above drawbacks and an object of this invention is to provide a battery-connecting plate which has integrally incorporated therein by insert molding battery-connecting busbars, voltage-detecting-circuit-constituting terminals and others, so that these components are less exposed to the outside, and is safe and easy to mount, and to provide a method of producing such battery-connecting plate.
Another object of this invention is to provide a battery-connecting plate which has a low parts count and low connections count, is highly reliable in electric connection, and does not cause improper connection and improper wiring to batteries.
Yet another object of this invention is to provide a battery-connecting plate which does not cause concentration of stress at that part of connection wires whereat the connection wires extend out of the molded resin plate.
Yet another object of this invention is to provide a method of producing a connecting plate according to which a commonly used wire covered with polyvinyl chloride or polyethylene can be used in place of a special heat-resistant wire such as polyimide-covered wire and which can thus be produced at a low cost.
A further object of this invention is to provide a wire protector which enables the production of the connecting plate as mentioned above.
In order to attain the objects, according to an aspect of this invention, there is provided a battery-connecting plate which comprises: busbars for connecting batteries together; and a wire protector which holds in a predetermined layout therein terminals and their connection wires for detecting voltage of desired ones of the batteries, the busbars and the wire protector being fixed in a resin plate by insert molding, with the busbars arranged in correspondence with the batteries and with the terminals held in contact with related ones of the busbars.
Preferably, the terminals each comprises a contact portion superimposed on the respective busbar, a wire connecting portion at which connected to the respective connection wire, and an element mount portion linking the contact portion and the wire connecting portion, and the connecting plate further comprises circuit protector elements which are, after completion of the insert molding, connected to the respective element mount portions of the terminals.
Preferably, the connection wires connected to the respective terminals are let out of the resin plate at one side thereof.
According to another aspect of this invention, there is provided a method of producing the battery-connecting plate as mentioned above, which comprises the steps of: providing busbars which connect batteries together; attaching terminals to one end of wires to produce terminal-attached wires for detecting voltage of desired ones of the batteries, the terminals each having a contact portion, a wire connecting portion at which attached to the respective wire, and an element mount portion linking the contact portion and the wire connecting portion; placing the terminal-attached wires in a predetermined layout in a wire protector, with tail portions of the wires let out at one side of the wire protector; setting the busbars and the wire protector in a mold such that the busbars are in position corresponding to an arrangement of the batteries, and the terminals have their contact portions superimposed on the respective busbars; injecting resin into the mold to produce a molded piece with the busbars and the terminal-attached wires embedded therein, with the contact portions of the terminals on the respective busbars and the element mount portions of the terminals left uncovered by the resin; and cutting the element mount portion of each of the terminals and connecting a respective circuit protector element to the element mount portion in a bridging manner across the cut.
Preferably, the busbars each has at least one electrode connection hole and the contact portions of the terminals each has a central hole, and wherein the contact portions are superimposed on the respective busbars with their holes aligned to each other.
Preferably, the element mount portions of the terminals each comprises a link piece at which the element mount portion is cut.
According to yet another aspect of this invention, there is provided a wire protector which comprises: a protector body including a trunk receiver for receiving trunk wires and a plurality of branch receivers continuous to the trunk receiver for receiving branch wires from the trunk wires, the plurality of branch receivers each including a terminal holder provided at a free end thereof and an expandable positional deviation absorbing portion arranged at an intermediate length thereof; and an open/close cover including a main cover for covering the protector body from the trunk receiver to the positional deviation absorbing portions of the branch receivers and a plurality of subcovers for covering the respective branch receivers from the terminal holder to the positional deviation absorbing portion, the main cover and the subcovers being rotatably linked via hinges to the protector body at positions corresponding to the trunk receiver and the respective branch receivers.
Preferably, the wire protector further comprises a wire letting-out portion provided at one end of the trunk receiver, the wire letting-out portion having a plurality of wire placement grooves, and a lit provided on the main cover corresponding to the wire letting-out portion.
Preferably, the positional deviation absorbing portion of each of the branch receivers comprises a pair of bent portions formed in a staggered manner in opposed side walls of the branch receiver and stoppers provided projecting in a staggered manner from one to the other of inner surfaces of the bent wall portions.
Preferably, the wire protector further comprises a positioning rib provided on the protector body or the open/close cover for positioning the wire protector in a mold.
The above and other objects, features and advantages of this invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings.